1. Field
The disclosed concept pertains generally to electrical switching apparatus and, more particularly, to electrical switching apparatus including an arc chamber. The disclosed concept also pertains to arc chambers for electrical switching apparatus.
2. Background Information
Electrical switching apparatus in which separable contacts are exposed to air and are structured to open a power circuit carrying appreciable current typically experience arcing as the contacts separate. These electrical switching apparatus, such as for instance, circuit breakers, commonly incorporate arc chutes to help extinguish the arc. Such arc chutes typically comprise a number of electrically conductive plates held in spaced relation around the separable contacts by an electrically insulative housing. The arc transfers to the arc plates where it is stretched and cooled until extinguished. A considerable volume of gas is generated by the arc. The pressure generated by this arc gas must be relieved to avoid catastrophic damage to the electrical switching apparatus casing.
As arc chamber size gets relatively smaller and smaller, it becomes more and more difficult for electrical switching apparatus, such as circuit breakers, to interrupt short circuits at relatively high system voltages, such as for example and without limitation, 10 kA/600 VAC single-phase. The failure mode for this type interruption is due to either thermal or dielectric breakdown across the separable contact gap that leads to re-ignition of arcing after current zero.
There is room for improvement in electrical switching apparatus including an arc chamber.
There is also room for improvement in arc chambers for electrical switching apparatus.